Automatic biological analyte testing meter with integrated lancing device and methods of use

ABSTRACT

The invention is directed to an integrated device for sampling and testing an analyte. The device generally comprises a housing, a lancing device for sampling an analyte, a test strip for substantially capturing at least a portion of the analyte, and a display unit for displaying a result corresponding to the captured portion of the analyte. The invention is further directed to methods for sampling and testing. For example, one method comprises performing a single operation to sample an analyte, to capture the sampled analyte, to perform testing on the sampled analyte, and to display a result corresponding to the performed test. A method such as this can be carried out using an integrated sampling and testing device of the invention, for example, by placing the device the device on a test site of a subject, such as a patient, and performing the single operation to obtain a test result. The invention has particular application in the sampling and testing of analytes in blood, such as the blood of a diabetic patient.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This non-provisional application is related to and claimspriority based on U.S. Provisional Application No. 60/424,414, entitled“Automatic Biological Analyte Testing Meter with Integrated LancingDevice and Methods of Use,” filed on Nov. 6, 2002, which is incorporatedherein in its entirety by this reference.

FIELD OF THE INVENTION

[0002] In general, this invention relates to skin lancing devices,analyte sensors and analysis meters for determining biological analytelevels, and more specifically, a portable device that integrates thefunctions of these separate devices in a single unit.

BACKGROUND OF THE INVENTION

[0003] Methods and devices used by a patient to measure a bioanalyte arewell known in the art. For example, currently available technologyallows a diabetic patient to monitor his own blood glucose level bydrawing a blood sample with a lancing device, using an electrochemicalsensor strip to capture the blood sample, and using an electronic meterconnected to the sensor strip to analyze the blood sample and displaythe result. Until recently, relatively large sample volumes wererequired to be drawn, generally 3 microliters or more of blood or otherbiological fluid. These fluid samples are obtained from a patient, forexample, using a needle and syringe, or by lancing a portion of the skinsuch as the fingertip and “milking” the area to obtain a useful samplevolume. These procedures are inconvenient for the patient, and oftenpainful, particularly when frequent samples are required. Less painfulmethods for obtaining a sample are known such as lancing the arm orthigh, which have lower nerve ending density. However, lancing the bodyin these preferred regions typically produces submicroliter samples ofblood, because these regions are not heavily supplied with near-surfacecapillary vessels. The recently introduced FreeStyle™ Blood GlucoseMonitoring System developed by TheraSense, Inc. of Alameda, Calif., iscapable of consistently, accurately and precisely measuring sample sizesof only ⅓ microliter using this preferred “alternate site testing”(AST). U.S. Pat. No. 6,299,757, issued Oct. 9, 2001 to TheraSense, Inc.and incorporated herein by reference describes the construction andoperation of the above FreeStyle system. U.S. Pat. No. 6,283,982 issuedSep. 4, 2001 to TheraSense, Inc. and incorporated herein by referencedescribes a lancing device that is used in the FreeStyle system.

[0004] A ⅓ microliter sample is about the size of a pinhead. Elderlypatients and those with reduced eyesight and dexterity can have problemsseeing and capturing such a small sample. Current testing proceduresinvolving a lancing device, disposable lancets, meter and disposabletest strips involve a lot of steps. It can be difficult for patients toremember all the steps and their proper order. Active patients testingoutdoors, for example, can have a tough time juggling all of thedifferent pieces during a test. Also, younger patients want to be ableto quickly and discreetly test themselves without drawing attention witha lot of paraphernalia and testing steps.

[0005] What is needed and has not been provided by the prior art is asimpler testing method using a compact, unitary testing device.

SUMMARY OF THE INVENTION

[0006] The testing instrument of the present invention provides a methodfor obtaining a sample and testing that sample using a single device.Further, the instrument automatically performs all the testing steps inthe proper order with the proper delays for each. The entire testingprocess is initiated by the patient with a single press of a button. Theinstrument automatically inserts and retracts a lancet into the skinwith the proper speed and force, waits a predetermined time for a fluidsample to form on the skin, aligns the fill channel of a test strip withthe small fluid sample and brings the two into contact to capture thesample, indicates to the patient when a sufficient sample has beencaptured, waits for electrochemical testing of the sample to becomplete, displays the test result to the patient, and records all ofthe test results for later review, analysis and/or uploading to acomputer network.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a top perspective view showing a unitary lancing device,test strip applicator and testing meter constructed according to thepresent invention.

[0008]FIG. 2 is a side elevation view showing the unitary handheldinstrument of FIG. 1.

[0009]FIG. 3 is a bottom perspective view schematically showing the cap,test strip and lancet on the instrument of FIG. 1.

[0010]FIG. 4 is a front cross-sectional view schematically showinglancet positioning features.

[0011]FIG. 5 is broken away perspective view schematically showing aconcentric spring lancing mechanism.

[0012]FIG. 6 is a perspective view schematically showing a torsionspring lancing mechanism.

[0013]FIG. 7A is a perspective view of a first embodiment of aninventive lancet and cap combination.

[0014]FIG. 7B is a perspective view of a second embodiment of aninventive lancet and cap combination.

[0015]FIG. 7C is a perspective view of a third embodiment of aninventive lancet and cap combination.

[0016]FIG. 7D is a perspective view of a multi-pointed lancet.

[0017]FIG. 7E is a schematic view showing possible locations of teststrip fill channels in relation to fluid samples created by the lancetof FIG. 7D.

[0018]FIG. 7F is a perspective view of a right-angle lancet.

[0019]FIG. 8 is a side elevation view schematically showing a lancetretention and ejection mechanism.

[0020]FIG. 9A is a front elevation view schematically showing a verticaltest trip trajectory.

[0021]FIG. 9B is a front elevation view schematically showing an arcuatetest trip trajectory.

[0022]FIG. 9C is a graph showing blood sample location versus fillsuccess rate for vertical trajectory test strips.

[0023]FIG. 9D is a graph showing blood sample location versus fillsuccess rate for arcuate trajectory test strips.

[0024]FIG. 10 is a front cross-sectional view schematically showing teststrip guiding features.

[0025]FIG. 11 is a bottom perspective view schematically showing thestrip motion and cap removal interlock on the instrument of FIG. 1.

[0026]FIG. 12 is a perspective view of a test strip moving mechanism.

[0027]FIG. 13 is a side elevation view of the test strip mechanism ofFIG. 12.

[0028]FIG. 14 is schematic view showing a test strip fill channellocation coding and translation scheme.

[0029]FIG. 15 is fragmentary side elevation view showing the use of aShape Memory Alloy to activate a test strip mechanism similar to that ofFIG. 12.

[0030]FIG. 16A is a perspective view showing an alternative embodimentof a test strip moving mechanism in the loading position.

[0031]FIG. 16B is a perspective view showing an alternative embodimentof a test strip moving mechanism in the testing position.

[0032]FIG. 17A is a perspective view showing another alternativeembodiment of a test strip moving mechanism in the loading position.

[0033]FIG. 17B is a perspective view showing another alternativeembodiment of a test strip moving mechanism in the testing position.

[0034]FIG. 18 is a perspective view showing yet another alternativeembodiment of a test strip moving mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Referring to FIG. 1, an integrated device 10 is shown thatfunctions as an automatic lancing device, test strip applicator andtesting meter. Integrated device 10 includes function buttons 12 and 14,liquid crystal display 16, display backlight button 18, actuator button20, cocking collar 22 and lancing depth control thumbwheel 24.Preferably device 10 has a plastic housing 26 having upper shell 28 andlower shell 30, forming a main body portion 32 and head portion 34.

[0036] Referring to FIG. 2, integrated device 10 has a lancet ejectionlever 36, a clear protective cap 38, and a strip return and cap removallever 40. Disposable electrochemical test strip 42 with side fillchannels 44 is shown in the loading position. The construction andmanual use of a side-file test strip 42 is fully described in U.S. Pat.No. 6,338,790 issued on Jan. 15, 2002 to TheraSense, Inc., and U.S.application Ser. No. 09/434,026, filed Nov. 9, 1999, both incorporatedherein by reference. Preferably, an existing test strip, such as theFreeStyle™ brand test strip developed and marketed by TheraSense, Inc.,is used with the present invention rather than a propriety formatdesigned especially for the integrated device. Advantages to usingexisting test strips include utilizing existing research anddevelopment, manufacturing, distribution, and inventory systems andhaving larger economies of scale, thereby allowing for a lower cost teststrip. Also, a large user base of patients are already familiar with theexisting strips, and if they desire, can alternately use the same stripsin existing manual meters and in the automatic device.

[0037] Referring to FIG. 3, features of clear protective cap 38 areshown. Also shown is a vertically oriented, disposable lancet 46 havinga plastic main body 48, a sharp 50 and removable cap 51 for coveringsharp 50 when not in installed in device 10. Device cap 38 has a recess52, preferably for resting on a patient's arm or leg. In use, the device10 is held as shown in FIG. 2, and preferably oriented generally aboveand perpendicular to the arm or leg. Aperture 54 is provided in thebottom of cap 38 for allowing at least the sharp 50 of lancet to passthrough to the patient's skin during actuation. Slotted opening 56 isprovided in one side of cap 38 to allow test strip 42 to pass from theoutside loading position to the inside sample gathering position. Otherthan these two openings, cap 38 completely surrounds lancet 46 before,during and after testing.

[0038] To achieve good lancing results, a pressure applicator ring 57should be provided around aperture 54. Ring 57 helps provide the properskin tension and capillary blood pressure to ensure that lancet 46pierces the skin with minimal pain and a sufficient amount of blood isexpressed from the wound. In the preferred embodiment, ring 57 issemi-toroidal in shape, has a major diameter of about 11 millimeters,stands about 2 millimeters off of cap 38, and has a width or minordiameter of about 1 millimeter. It is also advantageous to provide aland 1 to 2 millimeters in width between aperture 54 and ring 57. Forbest results, ring 57 and the enclosed land should be continuous, butthey can also be segmented as shown. For further disclosure of pressureapplicator ring design, see U.S. Pat. No. 6,283,982 issued Sep. 4, 2001to TheraSense, Inc. and entitled “Lancing Device and Method of SampleCollection,” incorporated herein by reference.

[0039] Lancet Guiding and Puncture Site Location Control

[0040] Referring to FIG. 4, the lancing operation of integrated device10 will be described. Since integrated device 10 is to automaticallybring the fill channel opening 44 of a test strip 42 (shown in FIG. 2)into contact with a small blood droplet brought up from a lancetpuncture in human skin, the device should have very good control overthe location of that puncture. Otherwise the mechanism would have littlechance of successfully bringing fill channel 44 to the droplet. Controlover the puncture site location is achieved, in part, by controlling thetolerances of mechanical features on lancet 46 and then guiding lancet46 closely over the few millimeters of its travel immediately before itpunctures the skin.

[0041] On the plastic lancet body 48 itself, the overall dimensions ofsome guiding feature, located as close to the puncturing tip aspossible, should be held to very close tolerances. Features in device 10mate closely to this guiding feature, but allow it to slide in thedirection of lancet travel, giving tight control over the location ofthe lancet body 48. The location of the lancet sharp 50 within theplastic lancet body 48 is then carefully controlled with respect to theguiding feature, and finally the point of sharp 50 is located preciselywith respect to the outside of sharp 50.

[0042] In the embodiment of integrated device 10 shown in FIG. 4, theguiding feature on the lancet 46 is a cylindrical collar 58 about 3 mmfrom the needle point, concentric with needle 50. The outside diameterof collar 58 is controlled to ±0.05 mm and needle 50 is concentric tothe outside diameter of collar 58 within ±0.05 mm. The needle point iscreated by grinding 3 radially symmetric faces, each canted 10° from theneedle circumference toward the axis of needle 50. These faces meet at acommon point located on the axis of needle 50 and defining the center ofthe needle's diameter.

[0043] The lancet guiding collar 58 slides inside a cylindrical bore 60in device 10 preferably with a diametral clearance of no more than 0.13mm. The lancet collar 58 and bore 60 engage at this close fit only forthe final 5 mm of the lancet's travel (starting when the needle point isabout 2 mm above the skin surface), as earlier engagement would reducethe kinetic energy of lancet 46 through friction and air pressure.

[0044] Referring to FIG. 7C, an alternative lancet 62 having ablade-shaped sharp 64 and plastic body 66 can be used instead of theneedle-shaped lancet 46 described above. Testing has shown that bladedlancet 62 may draw more blood than needle lancet 46. More importantly,because of constraints in the insert molding processes in which themetal sharps 50 and 64 are molded within plastic housings 48 and 66,respectively, tighter tolerances between the sharp and outside surfaceof the lancet housing can be obtained by using bladed lancet 62. Thisaids in more precisely maintaining the location of the blood drop formedon the skin after lancing, thereby allowing more precise alignmentbetween test strip 42 and the blood droplet for more reliable filling offill channel 44.

[0045] Concentric Spring Lancing Mechanism

[0046] Referring to FIG. 5, a first lancet driving and retractionmechanism is shown. Feedback from marketing focus groups shows thatcustomers desire an integrated device having a low profile head. Inorder to make the head 34 of integrated device 10 as short as possible,the lancet drive mechanism needs to have a short height. A typical drivesystem is comprised of a drive spring and a retraction spring, oftenplaced in series (a line) or parallel (lying next to each other). In thefirst mechanism embodiment shown in FIG. 5, lancet 46 is received withinlancet holder 68 which is captivated within drive spring 70, which inturn is nested within retraction spring 72. This concentric arrangementminimizes the vertical space the components occupy, and minimizes anyeccentric forces that might disturb the predictable linear motion oflancet 46 on firing.

[0047] Torsion Spring Lancing Mechanism

[0048] Referring to FIG. 6, a second lancet driving mechanism is shown.A typical wound-wire coil spring, such as springs 70 and 72 describedabove, applies a non-uniform force that depends on the amount it isdeflected. It also can compress only to a minimum height determined bythe wire diameter and number of coils (solid height). One way to obtainmore uniform spring force and avoid the limitations of a spring's solidheight is to use a torsion spring 74 to drive lancet holder 68′. Torsionspring 74 can be adjusted for force and travel without significantlyaffecting the overall mechanism size because the body of the spring doesnot lie in-line with the rest of the mechanism.

[0049] Large Lancet Cap for Handling

[0050] Referring to FIGS. 7A, 7B and 7C, alternate embodiments oflancets and caps are shown. Another factor that affects the overall sizeof the lancing mechanism is the length of the lancet itself. Traditionaldisposable lancets, such as shown in FIG. 3, have an elongate body 48and a short cap 51. In order to reduce the profile of device head 34, ashortened lancet 76 can be used that is just long enough to engagelancet holder 68 (shown in FIG. 6.) This short length might make thelancet difficult for the user to handle and install, so the protectivecap 78 (that is removed before use) should be made much larger thanusual to aid handling. Cap 78 may be an integrally molded, pull-off tabsuch as shown in FIG. 7A, or may be a hollow cap 80 with large handlemolded separately or in the same cavity as lancet 76 and placed overlancet 76 after molding, such as shown in FIG. 7B. A hollow cup or solid“pin cushion” type area 82 can be provided at the opposite end of cap78, as shown in FIG. 7A, to cover the sharp during removal from thedevice and disposal.

[0051] Referring to FIG. 7C, a lancet 62 having a blade-shaped sharp 64,short body 66 and large cap 84 is shown. Traditional and previouslydescribed lancets with needle-shaped sharps have their caps removed bytwisting. Twisting off the cap of a bladed lancet would likely damage ormove the skin piercing edge, resulting in a painful and/or ineffectivelance, or inaccurately placed droplet of blood. To assist patients whomay be used to twisting caps off of lancets, non-twist features havebeen incorporated into lancet 62. First, enlarged cap 84 is formed inthe shape of an arrow, reminding patients to pull cap 84 off of lancet62 rather than twisting. Second, non-circular mating collars 86 and 88are provided on lancet body 66 and cap 84, respectively. When cap 84 ismated with body 66, these collars 86 and 88 are keyed or aligned witheach other. Twisting would cause these non-circular collars 86 and 88 tobe misaligned, suggesting that this action should not be undertaken.Third, a widened portion 90 is provided on sharp blade 64 away from thenarrow distal end, providing resistance to twisting, or making damage tosharp 64 from twisting unlikely. Widened portion 90 provides otherbenefits as well, such as acting as a redundant maximum sharppenetration depth control in the event of failure of other depth controlmeasures. Widened portion 90 also aids in fabrication of lancet 62, asthis configuration is less susceptible to chattering during grinding.

[0052] Lancet cap 84 is also provided with pin-cushion type areas 82′and 82″, either of which can be used for receiving sharp 64 after useand prior to disposal. Area 82″ offers the advantage of allowing theuser to extend cap 84 up into device cap 38 to cover sharp 64 whilelancet 62 is still in place in integrated device 10. In this manner,used lancet 62 and cap 84 can be ejected from device 10 together as aunit so that the user need not handle small lancet 62 separately whiletrying to align it with cap 84.

[0053] Bladed Lancet Oriented Parallel to Strip

[0054] If the width of the cutting edge of sharp 64 is such that itcreates an oblong rather than circular blood droplet footprint, thecutting edge should be aligned parallel to test strip 42 (i.e. parallelto the axis of device 10) rather than perpendicular to it, since this isthe critical alignment axis, as will be described later. The flat shapeof lancet body 66 allows for such alignment and prevents misalignment.

[0055] Multi-Pointed Sharp

[0056] Referring to FIG. 7D a lancet 116 having a multi-pointed sharp isdisclosed. In this embodiment the lancet has two points 118, although inother embodiments (not shown) three or more points 118 could be arrangedinline or in other patterns. Each point 118 creates its own skinpuncture and blood droplet 104. (Two blood droplets 104, if they arespaced closely together and/or become large enough, may merge into asingle oblong or round blood drop.) If integrated device 10 is arrangedso that points 118 are aligned parallel to strip 42, the blood droplet104 and fill channel 44 positioning shown in FIG. 7E results. As shown,the longitudinal position of fill channel 44 relative to blood droplets104 can be widely varied while still maintaining enough contact with atleast one blood droplet 104 to cause fill channel 44 to wick upsufficient blood. Therefore, the use of a multi-pointed sharp allows thepositional tolerances of strip 42 and/or lancing to be relaxed whileimproving strip fill performance.

[0057] Right-Angle Lancet

[0058] Referring to FIG. 7F, a right-angle lancet 89 is disclosed. Themain advantage of this configuration is that it has an elongated bodysimilar to that of traditional lancet 46 (shown in FIG. 3) making iteasy to hold and manipulate, but this long dimension is orientedperpendicular to the lancing axis, thereby contributing to thepreviously stated goal of making device 10 low profile in height. Thebody of lancet 89 should be flat or keyed to allow the lancet holdingmechanism to keep sharp 50 oriented properly with the lancing axis.Lancet 89 can be driven downward in a pure vertical translation along astraight lancing axis, or it can be rotated about a horizontal axis suchthat sharp 50 travels in an arc and becomes perpendicular to thepatient's skin just as it punctures the skin.

[0059] Lancet Retention and Ejection

[0060] Referring to FIG. 8, the mechanism by which a disposable lancet76 is retained within the plunger portion 91 of the integrated devicelancing subsystem is shown. Lancet body 77 is generally flat and has anotch 92 on each edge for receiving barbs 94 on the plunger's flexibleretaining arms 96. The angles of the lancet's notches 92 and the arms'barbs 94 are chosen to draw lancet 76 into the plunger.

[0061] To eject lancet 76, the lancing subsystem mechanism urges lancet76 out of plunger 91, forcing retaining arms 96 to flex outward. Oncelancet 76 has moved far enough, barbs 94 bear on the tapered tail 98 oflancet 76 and their inward force translates to a longitudinaldisplacement of lancet 76—they will cause lancet 76 to eject.

[0062] The mechanism may use a linear plunger to eject the lancet(pushing in the downward direction in FIG. 8), or a wedge that bearsbetween some feature on lancet and the plunger body. For instance, tofurther reduce the height of plunger mechanism 91, a wedge-shaped ejectlever could extend perpendicularly into the plane of FIG. 8 and contactrear tapered edge 100 to urge lancet 76 downward and out of device 10.Preferably, an interlock mechanism is incorporated so that lancet 76cannot be ejected while cap 38 is still in place. Alternatively, theejection lever can be located inside cap 38 to achieve this same result.

[0063] Strip Loading Protected from Sharp

[0064] Referring again to FIG. 3, loading of test strip 42 will now bediscussed. In the compact integrated device 10, test strip 42 and sharp50 are located fairly close together. In order to eliminate thelikelihood of the user accidentally sticking himself on the lancet sharp50 while inserting a test strip 42, integrated device 10 is arranged sothat a test strip 42 can be inserted without removing the protective cap38 from head 34 of the device.

[0065] Cap 38 covers the lancet sharp 50 at all times and is removedonly to replace the lancet 46. Test strip 42 is inserted into a slot 102in lower housing shell 30 on the outside of cap 38, and the devicemechanism moves strip 42 from this loading position into the interior ofcap 38 and to the testing position near lancet sharp 50. The samemechanism moves test strip 42 away from sharp 50 and returns it to theload position for disposal after a test.

[0066] Test Strip Trajectory

[0067] Referring to FIGS. 9A and 9B, strip trajectories will bediscussed. One of the biggest challenges in developing an automated,integrated device is creating an autonomous mechanism that can introducea test strip 42 into a small blood sample and get an acceptably highrate of successful fills (blood entering test strip test chamber).Laboratory experiments indicate that the trajectory along which strip 42moves into contact with the blood droplet 104 has a significant effecton this success rate.

[0068] Referring to FIG. 9A, initial experiments held a test strip 42 ata 65° angle to the sample platform 106, and moved strip 42 along astraight line perpendicular to platform 106. The edge 108 of strip 42entered droplet 104 from above and stopped moving once it contacted thesample substrate (a glass slide). This arrangement produced erratic fillrate results, and showed a limited acceptable range of mislocationtolerance between droplet 104 and the strip 42 nominal location, asshown in FIG. 9C.

[0069] Referring to FIG. 9B, in subsequent experiments the test fixturewas modified so it held test strip 42 at a 35° angle and moved it alonga 25 mm radius arc whose axis was parallel to strip 42 and sampleplatform 106. The axis location was chosen so that edge 108 of strip 42was tangent to sample platform 106 at the lowest point of thetrajectory. When in use, strip 42 would be moving approximately parallelto and touching the surface of the sample substrate as fill channel 44on strip edge 108 contacted droplet 104. This trajectory provides muchmore consistent results and a higher successful fill rate, as well as asignificantly larger tolerance for mislocation, as shown in FIG. 9D. Itis believed that the wider tolerance is due to the “squeegee” action ofthis trajectory, as it tends to scrape blood off the substrate and pushit along in front of strip 42 until strip 42 stops moving.

[0070] Referring to FIGS. 12 and 13, a test fixture demonstrating analternative strip trajectory is disclosed. In this mechanism, one end oftest strip 42 is received within electrical connector 120 which isattached to mount block 122. Mount block 122 is slidably attached topivot arm 124, which in turn is pivotably attached to base plate 126with pivot bolt 128. Compression spring 130 biases mount block radiallyoutward from pivot bolt 128. Guide pin 132 is attached to mount block122 and travels in cam slot 134 formed in base plate 126, causing spring130 to compress as mount block 122 and guide pin 132 travel from left toright along cam slot 134. Torsion spring 136 mounted on pivot bolt 128drives pivot arm 124 counter-clockwise when release pin 138 is pulledfrom hole 140 in pivot arm 124, such as by an electric solenoid, motor,or manual release lever.

[0071] The trajectory of strip 42 in this embodiment is controlled bycam slot 134. It can be seen that the right end of cam slot 134 has aportion 142 that angles downward just before a short horizontal portion144 at the right extremity. Angled portion 142 yields a strip trajectorythat prevents device cap 38 from having a knife-like edge along theslotted opening where test strip 42 partially emerges from cap 38 tocontact the patient's skin. Short portion 144 allows strip 42 tosqueegee along the patient's skin before it comes to rest. In thepreferred embodiment, this travel distance along the skin is about 1 mm.Making this distance longer increases the risk that strip 42 maypossibly be impeded by a skin irregularity, such as a raised mole.Making this distance shorter increases the risk that strip 42 landsdirectly on sample 104 and does not capture the entire sample whenmoving along the skin. In the preferred embodiment, strip movementmechanism 160 is designed to have test strip edge 108 come to rest inthe center of sample 104, with tolerances such that edge 108 mayundershoot the sample center by 0.005 inch and may overshoot it by 0.010inch.

[0072] In this embodiment, the remainder of cam slot 134 (to the left ofangled portion 142) is not an arc concentric with pivot bolt 128 becauseit is desirable to have the test strip loading location farther to theleft of the lancing location to allow sufficient room for the user'sfingers to insert the strip. This non-concentric slot 134 is the reasonfor the slidable, spring loaded arrangement between mount block 122 andpivot arm 124.

[0073] Other strip angles and trajectories can be alternatively used,keeping in mind that strip fill performance is improved when the stripapproaches the target sample from the side. Also, good machine designpractice dictates that the maximum pressure angle (the angle between aline drawn from the axis of rotation to the point of contact, and a lineorthogonal to the cam surface at the point of contact) be no more than30°. In other alternative embodiments, the entire strip need not bemoved. For instance, the proximal end of strip 42 can be held stationarywhile the distal end is deflected away from and/or toward droplet 104with cams, rollers, guides or other suitable devices. Or, as shown inFIGS. 16A, 16B, 17A, 17B, or 18, the strip can be translated in avertical or inclined line and the squeegee action can be accomplished bya compliant member such as a leaf spring or compression spring.Alternatively, the distal end of strip 42 may follow a helical path asthe proximal end is simultaneously lowered and rotated (not shown.)

[0074] Strip Guiding and Location Control

[0075] To aid in aligning test strip 42 more precisely in itslongitudinal direction with the target blood droplet, connector 120 ispreferably biased outwardly when in the strip loading position (as shownin FIG. 12) and allowed to be urged inwardly in the direction of arrow Aas mount block 122 travels to the blood acquisition position. This canaccomplished by wave washers between pivot bolt 128 and pivot arm 124,or by other compliant measures such as flexure 146 formed in mount block122. As mount block 122 moves downwardly, cam surface 148 on its distalend can contact a mating feature on device cap 38 to move test striplongitudinally into a known and repeatable position. In this manner thenumber of parts requiring closely controlled tolerances on theirinterfaces for this longitudinal positioning can be limited to strip 42,connector 120, mount block 122 and cap 38, instead of a whole chainincluding the above parts and others having moving interfaces such aspivot arm 124, pivot bolt 128, base plate 126, upper housing shell 28,lower housing shell 30, etc., which would create a much larger tolerancestack-up and increase costs of fabrication and assembly. Preferably, thecam surface 148 could be located directly on connector 120 to furthereliminate the tolerances associated with mount block 122.

[0076] Referring to FIG. 10, additional strip guiding features aredisclosed. Not only should the integrated automated system have goodcontrol over the lancing site location as described above, it shouldalso tightly control the location of the test strip fill channel 44. Toaccomplish this, integrated device 10 has a carefully sized channel 110that serves to guide test strip 42 from its load position down to thetest site and locate it exactly with respect to the lancing site. Duringstrip motion, channel 110 can even ensure that strip 42 is fully seatedin its connector by gradually reducing lengthwise clearance along thetravel path. Once strip 42 approaches the test position, its criticaledge 108 can be spring-loaded to register against surface 112 inside cap38 that tightly controls its location with respect to the lancet guidebore 60.

[0077] In the preferred embodiment shown, guide channel 110 andregistration surface 112 for test strip 42, guide bore 60 for lancet 46,and a registration surface for contacting cam surface 148 on mount block122 or connector 120, are all molded into the same single part(protective cap 38). This allows tight control of the dimensionalrelationship between these features by reducing the tolerance stack-upbetween them and gives the best opportunity of ensuring that strip 42will contact blood droplet 104.

[0078] Variable Strip Approach Timing

[0079] In order for the above-described strip approach to succeed, bloodsample 104 should be present on the skin before strip 42 moves intoposition. Since human physiology varies such that it cannot be predictedexactly how long after lancing an appropriate-sized droplet will appearon the patient's skin, integrated device 10 preferably can be adjustedby the user to account for this variation.

[0080] In the preferred embodiment of integrated device 10, aprocessor-based electro-mechanical system controls the amount of timethat elapses between firing of the lancet and the approach of test strip42 to the test site. Patients who bleed easily can adjust this durationto be relatively short (for example 5 seconds) and those who bleedslowly can adjust it to be longer (for example 20 seconds.)Alternatively, a purely mechanical system for this adjustable delay maybe used.

[0081] This adjustability allows the total integrated device test timeto be as quick as possible, not burdening all patients with a fixed waittime long enough for those who bleed slowly.

[0082] Strip Motion/Cap Removal Interlock

[0083] Referring to FIG. 11, a cap removal interlock will be discussed.In order to protect the strip handling mechanism and ease changing oflancet 46, strip 42 should be returned to its loading position beforethe user removes cap 38. The preferred embodiment of integrated device10 ensures this by combining strip return and cap removal into a singleuser-operated control. This control is a sliding button 40 that runs inan L-shaped slot 114. To return strip 42 from the testing position tothe load/unload position, the user slides button 40 along the long legof L-slot 114, as shown by arrow B. To remove cap 38, the user slidesbutton 40 along the long leg of L-slot 114 and then pushes it into theshort leg of slot 114. This way the user is forced to return strip 42 tothe load/unload position before he can remove cap 38.

[0084] Test Strip Ejection

[0085] Traditional blood glucose testing utilizing a test strip 42requires touching one end of strip 42 to the blood sample of interest.Once the test is complete, the bloodied test strip 42 needs to bedisposed of. For health and safety reasons, it would be preferable notto require the user to handle used strips 42 after testing. Accordingly,a strip-eject mechanism can be employed on integrated device 10 thatallows the user to remove a used strip 42 from device 10 withouttouching the strip. This mechanism can use pinch-rollers to drive strip42, a plunger to push strip 42 out of its connector, or similarwell-known mechanism.

[0086] Overall Operation

[0087] Referring mainly to FIG. 1, the overall operation of integrateddevice 10 to measure blood glucose will be described. The patient firstpushes cap removal lever 40 over and up along L-shaped slot 114 toremove device cap 38. If a used lancet 46 still remains in lancet holder68, ejection lever 36 is pushed downward to eject lancet 46 fordisposal. Preferably the ejection mechanism is designed such that itcannot be actuated while device cap 38 is still in place. A fresh lancet46 is inserted into lancet holder 68, and lancet cap 51 is removed.Lancet holder 68 should be designed such that it provides a retentionforce that is greater than the force required to separate cap 51 fromlancet 46, so that lancet 46 is not pulled from lancet holder 68 whenthe patient tries to remove cap 51. Device cap 38 is then reinstalled ondevice 10. Alternately, cap aperture 54 and lancet cap 51, 78, 80 or 84can be sized such that device cap 38 can be reinstalled before thelancet cap is removed from the lancet.

[0088] The patient next removes a fresh test strip 42 from itsdesiccated vial and inserts the proper end into a mating connector (notshown) within slot 102 in device housing 26. Preferably test strip 42includes a conductive bar across an outer face such that the insertionof strip 42 powers on device 10. Instructions guiding the patientthrough the testing process can be displayed on LCD 16. Alternately,function button 12 can be used to turn on device 10.

[0089] With a fresh lancet 46 and test strip 42 loaded, integrateddevice 10 is cocked by pulling up on cocking collar 22, and then placedover the test site on the patient, with recess 52 of cap 38 resting onthe skin. Preferred testing sites include the forearm, upper arm, outerthigh, calf, and around the base of the thumb. Once device 10 ispositioned, the patient presses actuator button 20 which causes lancet46 to drive downward penetrating the skin and then retract. After apredetermined and preferably user-settable delay for allowing blood toemerge from the lancing site on the skin, test strip 42 is brought downalong an arcuate path into contact with the blood sample. The patientholds device 10 in this position until device 10 emits an audible and/orvisual indication that a sufficient amount of blood has been drawn intofill channel 44 of test strip 42 (detected by electrical measurements onstrip 42.) Device 10 then performs the appropriate measurements on theelectrochemical process within test strip 42, and when complete displaysthe result on LCD 16. Further manipulation of data or settings can beperformed by pressing function buttons 12 and 14.

[0090] After a test is complete, lever 40 is pushed towards the shortleg of L-shaped slot 114 to return used strip 42 to the load/unloadposition outside of protective cap 38. Strip 42 can then be removed fromdevice 10 for disposal by pressing a strip eject lever or by manuallyremoving strip 42. Used lancet 46 can also be removed at this time fordisposal, as previously described.

[0091] Control Solution Test Scheme

[0092] Occasionally testing needs to be performed with a fresh teststrip 42 and a “control solution” instead of blood to ensure that device10 is calibrated and working properly. For this procedure, the patientuses function button 12 and/or 14 to indicate to device 10 that acontrol solution test will be performed. Cap 38 is removed, eitherbefore or after a fresh test strip 42 is inserted into device 10. Toavoid risk of accidental lancing, lancet 46 is preferably capped orremoved during this process. With cap 38 out of the way and test strip42 in the load/unload position, a drop of control solution can beapplied to fill channel 44 of test strip 42. This test proceeds muchlike the blood glucose test described above, but strip 42 is never movedfrom the load/unload position and lancet 46 is never fired. After thecontrol solution test, test strip 42 is ejected and cap 38 is replaced.

[0093] Fill Channel Location Coding

[0094] Referring to FIG. 14, a scheme for encoding test strips 42 withfill channel 44 location data is disclosed. In the manufacture ofdisposable test strips such as for testing blood glucose, it can bedifficult to produce large quantities of strips 42 all having their fillchannels 44 located a predetermined distance from an end of the strip 42within a narrow tolerance. Since the blood samples 104 to be acquired bystrips 42 are becoming quite small (e.g. 0.050 inches in diameter), awide fill channel location tolerance can make it difficult or impossiblefor an integrated testing device to automatically align the test strip42 with the blood droplet 44. This problem can be solved by providingintegrated device 10 with a motor or other prime mover to position thestrip 42 longitudinally, and encoding the fill channel location for eachstrip 42 in a calibration code specific to that strip or batch ofstrips. When the calibration code is entered by the user or detectedfrom strip 42 automatically, device 10 can then position the test strip42 accordingly.

[0095] Currently, many disposable test strips are sold with a code tocalibrate the meter to the electrochemistry found on that particulartest strip. This calibration code can be, for example, one of fournumbers. If the fill channel location is characterized and similarlycategorized as being within one of four possible ranges, it can beassigned one of four letters. The number and letter calibration codescan be merged together to form a 4 by 4 array. In this way, one of 16different numbers can be used for each test strip, with each numberuniquely identifying the electrochemistry calibration and fill channellocation.

[0096] As shown in FIG. 14, the user enters a calibration code, whichincludes positional data, via the user interface 150. Microprocessor 152then reads data from an EEPROM 154 which indicates how far to advancemotor 156 to align fill channel 44 to the target droplet 104. Homesensor 158 can be used to provide a location reference.

[0097] Shape Memory Alloy Firing Mechanism

[0098] Referring to FIG. 15, an alternative method for firing lancingmechanism or strip delivery mechanism is disclosed. In the preferredembodiment of integrated device 10, the lancing or plunger mechanism 91(shown schematically in FIG. 8) is cocked by pulling up on cockingcollar 22, and fired by pressing actuator button 20 (both shown in FIG.1.) The test strip moving mechanism 160 (shown in FIGS. 12 and 13), onthe other hand, is not directly actuated by the user but is insteadcontrolled by the device's microprocessor 152, which ensures a suitabledelay between lancet firing and test strip movement as described above.An electric solenoid can be employed between microprocessor 152 andrelease pin 138, but given the typical force required to move pin 138,the size of the solenoid and the batteries required to drive it isunwieldy. Since pin 138 does not need to be extracted with great speed,a motor and lead screw arrangement can be employed instead of asolenoid, but this introduces complexity, cost and reliability issues.To overcome the above drawbacks, a shape memory alloy (SMA) wire can beused to drive release pin 138.

[0099] In the preferred embodiment shown, a Nickel-Titanium alloy, knowas Nitinol, is used in the shape of a wire 162. At room temperature, anitinol wire can easily be stretched 3-5% beyond its fabricated length.Upon heating the wire above a certain temperature threshhold, the wirewill return to its fabricated length with some force. At the time teststrip 42 is to be moved, microprocessor 152 on printed circuit board 164initiates a current through anchor post 166, which passes through wire162 and returns to PCB 164 through a chassis ground. The current heatsup Nitinol wire 162, causing it to contract to its original length. Theshortened length of wire 162 pulls release pin 138 in the direction ofarrow C against the force of compression spring 168 located between baseplate 126 and stepped shoulder 170 on pin 138. When the end of pin 138moves enough to disengage from hole 140 in pivot arm 124, test stripmoving mechanism 160 moves the test strip as previously described. Whenthe current running through wire 162 is shut off, wire 162 cools and isagain stretched by the compression spring 168. This allows spring 168 topush pin 138 back out again (opposite the direction of arrow C) toengage pivot arm 124 when arm 124 is returned to the raised position.

[0100] Ferules 172 or clamps are preferably crimped onto ends of wire162 to provide attachment points. To vary the forces and contractionlengths achieved by Nitinol wire in a small space and to perhaps makeelectrical connections easier, each end of the wire can be connected toits own post 166 on PCB 164, and the wire can be run through a small,insulated pulley connected to the end of pin 138. Additional pulleys orturning points can be attached or formed within the device housing. Inanother alternative embodiment, electrical connectivity can be providedto the wire by attaching electrical wires near the ends instead ofpassing the current through the anchor points. Shapes other than wire,such as a rod, bar, sheet or coil can be used. Nitinol or other shapememory alloys can be used to provide a tensile or compressive force tomove pin 138. Alternately, a piezoelectric material can be used.

[0101] The preferred embodiment of integrated device 10 will have aspecified operating temperature range, for example between 0 and 40degrees Celsius. To ensure that wire 162 reaches the proper temperatureto contract and operate the release mechanism properly when device 10 isanywhere within the specified temperature range, conventional controlcircuitry would always apply the maximum electrical current required toheat the wire from the bottom of the temperature range to thetemperature required for wire contraction. However, device 10 wouldtypically not be operated at the bottom of the predetermined operatingrange, so much of the current applied to wire 162 during each use wouldmerely be drained from the device's batteries without providing anybenefit. To overcome this drawback, device 10 should utilize atemperature sensor (which can also be used for other testing functions)and a current switching circuit that supplies only enough current toelevate wire 162 from the ambient temperature to the contractingtemperature. Rather than supplying a constantly decaying current from acharged capacitor to wire 162, the device's microprocessor can beconfigured to sense the ambient temperature and control a switch withone of its outputs to provide a series of pulses of current to wire 162to cause its contraction. As ambient temperature decreases, themicroprocessor provides pulses of longer duration, approaching aconstant source of current as the ambient temperature approaches thebottom of the predetermined operating range. Alternatively, rather thanpulsing the current, the duration of the current can be controlled basedon the ambient temperature (i.e. a shorter duration for a higher ambienttemperature.) By employing this inventive circuitry, smaller batteriescan be used and/or longer battery life can be achieved, thereby makingdevice 10 more compact and less expensive.

[0102] The invention has been described with reference to variousspecific and preferred embodiments and techniques. However, it will beapparent to one of ordinary skill in the art that many variations andmodifications may be made while remaining within the spirit and scope ofthe invention.

1. An integrated device for sampling and testing an analyte comprising:a housing; a lancing device operatively coupled to said housing forsampling an analyte; a test strip operatively coupled to said housingfor substantially capturing at least a portion of the analyte; and adisplay unit mounted to said housing for displaying a resultcorresponding to the captured portion of the analyte.
 2. The device ofclaim 1, wherein the lancing device includes a cutting edgesubstantially aligned with said test strip.
 3. The device of claim 1,wherein the lancing device is operatively coupled to said housing by aspring mechanism.
 4. The device of claim 1, wherein the lancing deviceincludes body having a first axis and a sharp mounted to the body,wherein the sharp has a second axis, said second axis beingsubstantially perpendicular to said first axis.
 5. The device of claim1, wherein the lancing device includes a sharp, said sharp having aleast two points, each configured for sampling the analyte.
 6. Thedevice of claim 1, wherein said lancing device is configured to draw theanalyte through a test site of a patient by piercing the tissue thereof.7. The device of claim 1, wherein said test strip is physicallydisplaced relative to said housing to contact the analyte.
 8. The deviceof claim 7, wherein a fill channel of said test strip is substantiallyaligned with the analyte.
 9. The device of claim 1, wherein the resultdisplayed on said display unit corresponds with a physiological propertyof the captured portion of the analyte.
 10. The device of claim 9,wherein the physiological property of the captured portion of theanalyte includes at least one of: a glucose level; a carbohydrate level;a hemoglobin level; and a glycated hemoglobin level.
 11. The device ofclaim 1, further including a controller operatively coupled to saidhousing for controlling the operation of said lancing device.
 12. Thedevice of claim 1, further including a controller operatively coupled tosaid housing for controlling a movement of said test strip.
 13. Thedevice of claim 1, further including a controller operatively coupled tosaid housing for controlling the display on said display unit.
 14. Thedevice of claim 1, further including an input unit mounted to saidhousing for operating the lancing device.
 15. A method for sampling andtesting comprising: placing an integrated sampling and testing device ona test site of a patient; and performing a single operation of thedevice to sample an analyte from the test site, to perform analytetesting on the sample, and to display a result corresponding to theanalyte testing.
 16. The method of claim 15, wherein the performing asingle operation includes depressing an input button.
 17. The method ofclaim 15, wherein the analyte is sampled from the test site bydisplacing a test strip to contact the analyte.
 18. The method of claim15, wherein the analyte is sampled from the test site by piercing thetest site with a lancing device, moving a test strip to the pierced testsite to capture the analyte.
 19. A method of integrating sampling andtesting of an analyte comprising: performing a single operation tosample an analyte, to capture said sampled analyte, to perform testingon said sampled analyte, and to display a result corresponding to theperformed test.
 20. The method of claim 19, wherein said analyte isblood.